Corrosion Resistance of Brass
Brasses are resistant to corrosion in many media. Please consult Austral Wright Metals for detailed advice on your application. Brasses are particularly susceptible to corrosion by solutions containing ammonia or amines. Alloys with more than about 15% of zinc may suffer dezincification, which leaves a weak, porous corrosion deposit of copper. Resistance to dezincification is greatly reduced by the addition of a small amount of arsenic to the alloy. Stress corrosion cracking, particularly by ammonia and amines, is also a problem with the brasses. Alloys containing more than about 15% zinc are most susceptible. Use of the annealed temper, and annealing or stress relieving after forming, reduces susceptibility to stress corrosion cracking.
Gilding Metal Copper Alloy - Properties and Applications
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Also known as red brass, commercial bronze, gilding metal. C22000 combines a rich golden colour with the best combination of strength, ductility and corrosion resistance of the plain copper-zinc alloys. It weathers to a rich bronze colour, and can be supplied in pre-patinated colours ranging from deep brown to green. It has a lower rate of work hardening than the copper-zinc alloys with higher zinc content, such as 260 and 272. This is an advantage in multistage pressing applications without interstage annealing. It has excellent deep drawing characteristics and resistance to pitting corrosion and stress corrosion cracking when exposed to severe weather and water environments.
Corrosion Resistance of Gilding Metal Copper Alloy
As an alpha brass with low zinc content, C22000 has excellent corrosion in most media. It is less susceptible to stress corrosion cracking than the higher zinc brasses such as 70/30 brass C26000, and is not considered susceptible in marine atmospheres. However, it should not be used in contact with aqueous ammonia and amines. C22000 should not be used with acetic acid, acetylene, brines, calcium chloride, moist chlorine, chromic acid, hydrochloric acid, mercury or its compounds, nitric acid and sodium hypochlorite.
Brass and Arsenical Brass Alloy - Properties and Applications
Also known as cartridge brass, spinning brass, spring brass. C26000, 70/30 Brass and C26130, Arsenical brass, have excellent ductility and strength, and are the most widely used brasses. Arsenical brass contains a small addition of arsenic, which greatly improves corrosion resistance in waters, but is otherwise effectively identical. These alloys have the distinctive bright yellow colour normally associated with brass. They have the optimum combination of strength and ductility in the copper-zinc alloys, coupled with good corrosion resistance.
C26000 is used for architecture, drawn and spun containers and shapes, electrical terminals and connectors, door handles, plumbers hardware. C26130 is used for tube and fittings in contact with water, including potable water.
Corrosion Resistance of Brass and Arsenical Brass Alloy
C26000 has good corrosion resistance to weathering and very good resistance to many chemicals. It may undergo dezincification in stagnant or slowly moving salt solutions, brackish water or acidic solutions. Although it will resist most waters, C26130 is preferred as it contains a small arsenic addition which inhibits corrosion.
C26000 should not be used in contact with ammonia or ammonia compounds, as it may suffer stress corrosion cracking. Beware of corrosion inhibitors in piping systems containing carbon steels, which should be checked for compatibility with alloy C26000. 70/30 brass should not be used with acetic acid, acetylene, brines, calcium chloride, moist chlorine, chromic acid, hydrochloric acid, mercury or its compounds, nitric acid and sodium hypochlorite.
